Apparatus for gas treatment of products

ABSTRACT

An apparatus for gas treatment of products rises a housing having top, bottom and side walls; a conveyor belt for transporting the products along a first path in the housing; a tunnel having perforated walls and enclosing the conveyor belt along the first path; a gas circulation device communicating with the tunnel via the perforated walls for circulating gas into the tunnel in the form of gas jets impinging upon the products carried by the conveyor belt, and out of the tunnel in a return channel back to the gas circulation device; and a gas conditioning device positioned in the return channel. At least one substantially vertical part of the connecting walls of the high-pressure chamber is removable so as to provide access to the inside of the pressure chamber, and at least one of the side walls of the housing along the high-pressure chamber may be movable so as to widen the space between at least one wall and the high-pressure chamber.

The present application is the national stage under 35 U.S.C. 371 ofinternational application PCT/SE00/00110, filed Jan. 20, 2000, whichdesignated the United States, and which international application waspublished under PCT Article 21(2) in the English language.

BACKGROUND OF THE INVENTION

The present invention is related to gas treatment of products,specifically food and similar products, using gas jets which impingeupon the products for e.g. cooling, heating or drying them.

Devices for cooling or heating food products are known from e.g. U.S.Pat. No. 4,679,542 to Donald P. Smith et al. These devices comprise ahousing in which a high-pressure gas plenum communicates with upper andlower ducts defining a treatment area therebetween and having aplurality of nozzles for ejecting gas jets vertically into the treatmentarea. The food products to be treated are supported by a conveyor beltthat transports them through the treatment area.

The design of these known devices is quite complex, resulting indifficulties in meeting the high hygienic requirements of the foodindustry. Also, the maintenance of the prior art devices istime-consuming, and the intervals between successive shutdowns areshort.

Another apparatus for cooling, heating or drying of products is knownfrom U.S. Pat. No. 5,408,921 to Per-Oskar Persson et al. This apparatuscomprises a housing and a conveyor belt for transporting the productsthrough the housing along a path from an inlet opening to an outletopening in the housing. A tunnel encloses the conveyor belt at leastalong a part of the path from the inlet opening to the outlet opening.Cold air is circulated by fan means through perforations in the tunnelwalls opposite to the products carried on the conveyor belt such thatair jets impinge upon the surface of the products, and further out ofthe tunnel to air conditioning means for conditioning the air and thenback to the outside of the tunnel.

This prior art apparatus substantially eliminates or at least reducesthe above-noted problems of the devices known from e.g. U.S. Pat. No.4,679,542 to Donald P. Smith et al.

However, the known devices and apparatus are relatively bulky.

SUMMARY OF THE INVENTION

Therefore, one object of the present invention is to provide a compactapparatus for gas treatment of products.

Another object of the present invention is to provide such an apparatuswhich meets the high hygienic requirements of the food industry.

According to the present invention these objects are attained by anapparatus for gas treatment of products which a housing having top,bottom and side-walls; a conveyor belt for transporting the productsalong a first path in the housing; a tunnel having perforated walls andenclosing the conveyor belt along the first path; gas circulation meanscommunicating with the tunnel via the perforated walls for circulatinggas into the tunnel in the form of gas jets impinging upon the productscarried by the conveyor belt, and out of the tunnel in a return channelback to the gas circulation means, and gas conditioning means positionedin the return channel for conditioning the gas circulated by the gascirculation means. Further, walls connecting with the perforated wallsof the tunnel and having an opening towards the gas circulation means,form a high-pressure chamber substantially above the tunnel and spacedfrom the walls of the housing. Finally, at least one substantiallyvertical part of the connecting walls of the high-pressure chamber isremovable so as to provide access to the inside of the pressure chamber.

By this configuration, a compact design is obtained which also provideseasy access to all parts of the apparatus, which is a condition forfulfilling the high hygienic requirements of the food industry.

Preferably, at least one substantially vertical part of the connectingwalls of the high-pressure chamber is slidable or articulated forproviding an access opening into the high-pressure chamber.

In a preferred embodiment, the vertical parts of the connecting walls onboth sides of and all along the tunnel in the high-pressure chamber areremovable.

Further, the conveyor belt is preferably foraminous, the top wall of thetunnel being perforated substantially over its whole area, and thebottom wall of the tunnel having perforated sections extendingtransversely of the first path, such that the gas jets may impinge uponboth the top side and the bottom side of the products on the, conveyorbelt.

In a most preferred embodiment, at least one of the side walls of thehousing along the high-pressure chamber is removable so as to widen thespace between said at least one wall and the high-pressure chamber. Thisresults in a very compact configuration, still fulfilling high demandson access to all parts of the apparatus.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of a first embodiment of an apparatusaccording to the present invention.

FIG. 2 is a cross-sectional view of the apparatus in FIG. 1.

FIG. 3 is a cross-sectional view corresponding to that in FIG. 2illustrating a second embodiment of an apparatus according to thepresent invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Referring to FIGS. 1 and 2, an apparatus for quick freezing of foodproducts, e.g. meat patties, comprises a housing 1 having a top wall 2,a bottom wall 3, two side walls 4 and 5, and two end walls (not shown).The top wall is supported on a stand 6. Each one of the side walls 4, 5has two sections 4a, 4b and 5a, 5b, respectively. Each one of these wallsections 4a, 4b, 5a, 5b is removable by being supported on twotelescopic arms 7 which are mounted on top of the top wall 2.

The side walls 4 and 5 are shown in ejected or open positions in FIG. 1and in retracted or closed positions in FIG. 2. Obviously, removing. oneor both of the side walls 4 and 5 by pulling them from their closedpositions to their open positions gives very good access to theequipment inside the housing 1. On the other hand, the apparatus is verycompact when the side walls 4 and 5 are pushed back into their closedpositions, as illustrated in FIG. 2.

The equipment within the housing 1 comprises a conveyor belt 8 extendingbetween a first end roller 9 at one end of the housing 1 and a secondend roller (not shown) at the other end of the housing 1. The conveyorbelt 8 follows a first upper path 10 between the end rollers fortransporting products to be frozen through the housing 1 from an infeedopening in one end wall to an outfeed opening in the opposite end wall.

A tunnel 11 encloses the conveyor belt 8 along the first path. Thistunnel 11 has substantially the same configuration as the tunneldisclosed in U.S. Pat. No. 5,408,921 which is incorporated herein byreference. Thus the tunnel 11 comprises a top wall 12 which isperforated substantially over its whole area, and a bottom wall (notshown) which has perforated sections extending transversely of the firstpath. Further, the bottom wall of the tunnel has a plurality of openingsalternating with said perforated sections and communicating with areturn channel 13.

A high-pressure chamber 14 is provided by substantially vertical sidewalls 15 and 16 each one connecting with the side edges of the openingsof the bottom wall of the tunnel 11, and a top wall 17 having an openingtowards a fan 18 constituting a gas circulation means. Thishigh-pressure chamber 14 is positioned substantially above the tunnel 11and is spaced from the side walls 4, 5 of the housing 1.

The return channel 13 leads from under the tunnel 11 laterally to theoutside of the side walls 15, 16 of the high-pressure chamber 14 upthrough an evaporator 19, 20 and then laterally inwards above the topwall 17 of the high-pressure chamber 14 towards the center of thehousing 1 and the suction side of the fan 18.

The lower parts 15a, 16a of the side walls 15, 16 of the high-pressurechamber 14 are articulated to the top parts 5b, 16b of the same sidewalls 15, 16, e.g. by axes 21. In their closed position, as illustratedin FIG. 2, the lower parts 15a, 16a of the side walls 15, 16 keep thehigh-pressure chamber 14 closed such that air introduced by the fan 18can generate a high pressure in the chamber 14 and thereby also generateair jets through the perforations of the upper (12) and lower walls ofthe tunnel 11 impinging upon the products carried by the conveyor belt 8therein. The lower parts 15a, 16a of the side walls 15, 16 aresubstantially horizontal in their open position, i.e. being swungoutwards from the tunnel 11, and now give access to the inside of thehigh-pressure chamber 14.

In operation, the apparatus is as illustrated in FIG. 2, i.e. the sidewalls 4, 5 of the housing 1 are in their closed positions and the lowerparts 15a, 16a of the side-walls 15, 16 of the high-pressure chamber 14are in their lower positions closing the high-pressure chamber 14. Thefan 18 then blows air into the high-pressure chamber 14 therebygenerating air jets from the perforations of the tunnel 11 impingingupon the objects on the conveyor belt 9 therein. The air exits from thetunnel through its bottom openings and flows laterally outwards abovethe bottom wall 3 and upwards in the channel 13 between the side wall 4of the housing 1 and the side wall 16 of the high-pressure chamber 14 tothe evaporator 20, and also in the channel 13 between the side wall 5 ofthe housing 1 and the side wall 15 of the high-pressure chamber 14 tothe evaporator 19. From the evaporators 19, 20 the cold air is suckedthrough the remaining parts of the channel 13 into the suction side ofthe fan 18.

As a consequence of the central position of the high-pressure chamber 14in the housing 1, the pressure on the inside of the walls 2-5 of thehousing 1 does not differ very much from the ambient. pressure outsidethe housing so that there is substantially no tendency for air leakagebetween inside and outside of the housing 1.

When shutting down the apparatus, the walls 4 and 5 are pulled out totheir open positions, the lower parts 15a, 16a of the side walls 15, 16of the high-pressure chamber 14 are swung upwards to their openpositions, and the top wall 12 of the tunnel 11 may also be swung up ortilted to an open position, as shown in FIG. 1. Thereby, all componentsof the apparatus are easily accessible for cleaning.

Referring to FIG. 3, the second embodiment of an apparatus according tothe present invention differs from the first embodiment in that the sidewalls 15 and 16 of the high-pressure chamber 14 are lids that areslidable lengthwise, i.e. parallel to the transportation direction ofthe conveyor belt 9. Further, the evaporators 19 and of the secondembodiment are positioned substantially above the high-pressure chamber14, thereby expanding the available space in front of the side walls 15,16, such that movable side-walls of the housing are not necessary.

It is to be understood that modifications, alterations, and changes canbe made in the above-described embodiments of the apparatus withoutdeparting from the scope of the invention as claimed herein. Thus,normally the gas is air but it may consist of other gases as well. Wherethe apparatus is used for freezing food products, the conditioning meansmay consist of a cooling battery, such as the exemplified evaporator.When the apparatus is used for heating food products, the conditioningmeans may consist of a heat exchanger or an electrical heater, Finally,where the apparatus is used for drying food products, the conditioningmeans may consist of a moisture regulating device. Other conditioningmeans are also possible.

1. An apparatus for gas treatment of products, comprising a housing (1)having top, bottom and side walls (2; 3; 4, 5), a conveyor belt (8) fortransporting the products along a first path (10) in the housing (1), atunnel (11) having perforated walls (12) and enclosing the conveyor belt(8) along the first path (10), gas circulation means (18) communicatingwith the tunnel (11) via the perforated walls (12) for circulating gasinto the tunnel (11) in the form of gas jets impinging upon the productscarried by the conveyor belt (8), and out of the tunnel (11) in a returnchannel (13) back to the gas circulation means (18), andgas-conditioning means (19, 20) positioned in the return channel (13)for conditioning the gas circulated by the gas circulation means (18),characterized by walls (15-17) being separated from the walls (2-5) ofthe housing (1), said separated walls (15-17) being connected with theperforated walls (12) of the tunnel (11) and having an opening towardsand connected to an outlet of the gas. circulation means (18) in orderto form a high pressure high-pressure chamber (14) substantially abovethe tunnel (11) and constituting a gas circulation channel from saidoutlet of the gas circulation means (18) to the perforated walls (12) ofthe tunnel (11), at least one substantially vertical part of the walls(15-17) forming the high-pressure chamber (14) being removable so as toprovide access to the inside of the high-pressure chamber (14).
 2. Anapparatus for gas treatment of products as claimed in claim 1, whereinsaid at least one substantially vertical part of the walls (15-17)forming the high-pressure chamber (14) is slidable for providing anaccess opening into the high-pressure chamber (14).
 3. An apparatus forgas treatment of products as claimed in claim 1, wherein said at leastone substantially vertical part of the walls (15-17) forming thehigh-pressure chamber (14) is articulated for providing an accessopening into the hihg-pressure high-pressure chamber (14).
 4. Anapparutus apparatus for gas treatment of products as claimed in any oneof claims 1-3, wherein the vertical parts of the walls (15-17) formingthe high-pressure chamber (14) are removable all along the tunnel (11).5. An apparatus for gas treatment of products as claimed in claim 4,wherein substantially vertical parts of the walls (15-17) forming thehigh-pressure channel (14) of the are removable on both sides of thetunnel (11).
 6. An apparatus for gas treatment of products as claimed inclaim 1, wherein the high-pressure chamber (14) has a top wall (17)positioned above the tunnel (11) and supporting the gas circulationmeans (18).
 7. An apparatus for gas treatment of products as claimed inclaim 1, wherein the conveyor belt (8) is foraminous, a top wall (12) ofthe tunnel (11) is perforated substantially over its whole area, and abottom wall of the tunnel (11) has perforated sections extendingtransversely of the first path (10).
 8. An apparatus for gas treatmentof products as claimed in 7, wherein the bottom wall of the tunnel (11)has a plurality of openings alternating with said perforated sectionsand communicating with the return channel (13).
 9. An apparatus for gastreatment of products as claimed in claim 1, wherein at least one of theside walls (4, 5) of the housing (1) along the high-pressure chamber(14) is removable so as to widen the space between said at least onewall (4, 5) and the high-pressure chamber (14).
 10. An apparatus for gastreatment of product as claimed in claim 9, wherein said side walls (4,5) of the housing (1) comprises comprise at least two adjoining sections(4a, 4b, 5a, 5b).
 11. An apparatus for gas treatment of products asclaimed in claim 9, wherein said removable side walls (4, 5) aredepending from telescopic arms (7) mounted on the top wall (2) of thehousing (1).
 12. An apparatus for gas treatment of products as claimedin claim 6, wherein the conveyor belt (8) is foraminous, a top wall (12)of the tunnel (11) is perforated substantially over its whole area, anda bottom wall of the tunnel (11) has perforated sections extendingtransversely of the first path (10).
 13. An apparatus for gas treatmentof products as claimed in claim 12, wherein the bottom wall of thetunnel (11) has a plurality of openings alternating with said perforatedsections and communicating with the return channel (13).
 14. Anapparatus for gas treatment of products as claimed in claim 13, whereinat least one of the side walls (4, 5) of the housing (1) along thehigh-pressure chamber (14) is removable so as to widen the space betweensaid at least one wall (4, 5) and the high-pressure chamber (14).
 15. Anapparatus for gas treatment of products as claimed in claim 14, whereinsaid side walls (4, 5) of the housing (1) comprises comprise at leasttwo adjoining sections (4a, 4b 5a, 5b).
 16. An apparatus for gastreatment of products as claimed in claim 15, wherein said removableside walls (4, 5) are depending from telescopic arms (7) mounted on thetop wall (2) of the housing (1).
 17. An apparatus for gas treatment ofproducts, comprising a housing having top, bottom and side walls; aconveyor belt for transporting the products along a path in the housing;a tunnel having perforated walls and enclosing the conveyor belt alongthe path; a gas circulation device communicating with the tunnel via theperforated walls for circulating gas into the tunnel in the form of gasjets impinging upon the products carried by the conveyor belt, and outof the tunnel in a return channel back to the gas circulation device; agas conditioning device positioned in the return channel forconditioning the gas circulated by the gas circulation device; ahigh-pressure chamber provided by top, bottom, and side walls disposedwithin the housing, wherein the side walls of the high-pressure chamberare spaced from the side walls of the housing, the high-pressure chamberin communication with the return channel and the perforated walls of thetunnel, with the gas circulation device maintaining the high-pressurechamber at a higher pressure than the return channel; and at least onesubstantially vertical part of the walls forming the high-pressurechamber being removable so as to provide access to the inside of thehigh-pressure chamber.
 18. An apparatus for gas treatment of products asclaimed in claim 17, wherein the gas conditioning device is a coolingbattery.
 19. An apparatus for gas treatment of products as claimed inclaim 17, wherein the gas conditioning device is a heat exchanger. 20.An apparatus for gas treatment of products as claimed in claim 17,wherein the gas conditioning device is an electrical heater.
 21. Anapparatus for gas treatment of products as claimed in claim 17, whereinthe gas conditioning device is a moisture regulating device.
 22. Anapparatus for gas treatment of products as claimed in claim 17, whereinthe at least one substantially vertical part of the walls forming thehigh-pressure chamber is slideable for providing an access opening intothe high-pressure chamber.
 23. An apparatus for gas treatment ofproducts as claimed in claim 17, wherein the at least one substantiallyvertical part of the walls forming the high-pressure chamber isarticulated for providing an access opening into the high-pressurechamber.
 24. An apparatus for gas treatment of products as claimed inclaim 17, wherein vertical parts of the walls forming the high-pressurechamber are removable all along the tunnel.
 25. An apparatus for gastreatment of products as claimed in claim 22, wherein vertical parts ofthe walls forming the high-pressure chamber are removable all along thetunnel.
 26. An apparatus for gas treatment of products as claimed inclaim 23, wherein vertical parts of the walls forming the high-pressurechamber are removable all along the tunnel.
 27. An apparatus for gastreatment of products as claimed in claim 24, wherein substantiallyvertical parts of the walls forming the high-pressure chamber areremovable on both sides of the tunnel.
 28. An apparatus for gastreatment of products as claimed in claim 17, wherein the high-pressurechamber has a top wall positioned above the tunnel and supporting thegas circulation means.
 29. An apparatus for gas treatment of products asclaimed in claim 17, wherein the conveyor belt is foraminous, a top wallof the tunnel is perforated substantially over its whole area, and abottom wall of the tunnel has perforated sections extending transverselyof the first path.
 30. An apparatus for gas treatment of products asclaimed in claim 29, wherein the bottom wall of the tunnel has aplurality of openings alternating with the perforated sections andcommunicating with the return channel.
 31. An apparatus of gas treatmentof products as claimed in claim 17, wherein at least one of the sidewalls of the housing along the high-pressure chamber is removable so asto widen the space between the at least one wall and the high-pressurechamber.
 32. An apparatus for gas treatment of products as claimed inclaim 31, wherein the side walls of the housing comprise at least twoadjoining sections.
 33. An apparatus for gas treatment of products asclaimed in claim 31, wherein the removable side walls are depending fromtelescopic arms mounted on the top wall of the housing.
 34. An apparatusfor gas treatment of products as claimed in claim 28, wherein theconveyor belt is foraminous, a top wall of the tunnel is perforatedsubstantially over its whole area, and a bottom wall of the tunnel hasperforated sections extending transversely of the first path.
 35. Anapparatus for gas treatment of products as claimed in claim 34, whereinthe bottom wall of the tunnel has a plurality of openings alternatingwith the perforated sections and communicating with the return channel.36. An apparatus for gas treatment of products as claimed in claim 35,wherein at least one of the side walls of the housing along thehigh-pressure chamber is removable so as to widen the space between theat least one wall and the high-pressure chamber.
 37. An apparatus forgas treatment of products as claimed in claim 36, wherein the side wallsof the housing comprise at least two adjoining sections.
 38. Anapparatus for gas treatment of products as claimed in claim 37, whereinthe removable side walls are depending from telescopic arms mounted onthe top wall of the housing.